Connecting systems and in particular fiber optic connecting systems present significant installation and maintenance problems. There are especially problems with field cleaning. Installation techniques include fiber-cable preparation, termination of the fiber in the pin or socket. terminus (or wire in pin or socket contact) and insertion of the termini contacts in the connector housing. Typically, there is some cleaning to be done to the terminus or contact after the fiber is secured in place and the cleaning can be done prior to the insertion of the terminus or contact in the connector half. Hereafter, the term pin terminus for fiber can also be a pin contact for electrical connecting and the term socket terminus for fiber can also be a socket contact for electrical connecting.
Maintenance problems involve the need to be able to clean the connector after it has been installed and used for a period of time. Whether the connector is fiber optic or electrical, a single-channel (one terminus pair which when joined together represent a single optical fiber line for signal transmission) or a multi-channel connector (multiple number of fiber-optic termini pairs) there is some cleaning which is necessary for field applications. In multi-channel connectors, there is usually a pin terminus on one side of the mated connector pair and a socket terminus on the other side of the mated connector pair. The pin terminus is typically protruding from the pin insert which contains the plurality of pin termini and is therefore relatively easy to clean without any special treatment.
The socket terminus is typically recessed within the alignment bushing in the socket insert which contains the plurality of socket termini. Since these are recessed they are not easily accessible for cleaning which requires not only cleaning of the end face of the fiber in the terminus but also requires cleaning of the alignment bushing cavity. There are situations in field applications where the connector halves can be exposed to mud and debris when uncoupled and unmated. Under these circumstances the alignment bushing can be filled or partially filled with contaminants and it can be very difficult to be certain of getting all the contaminating material out even if some can be removed. In fiber-optic interconnections the mating fibers must be totally clean and free of any contaminants, even the smallest particles can significantly degrade the signal and thus introduce unacceptable losses to signal transmission.
There is the possibility of removing the termini completely from the connector half and cleaning them outside. However, this is very impractical since the connector half typically has an accessory backshell which is difficult to remove and may even be sealed by long use and not removable at all. Furthermore the termini must be removed with the use of a special removal tool which is difficult to use and can tear up the fluorosilicone rubber insert with repeated insertions and removal of the termini. The whole procedure of removing the termini each time the connector half is cleaned, is time consuming, difficult and totally unacceptable for field maintenance conditions.
Multi-channel connectors usually have some rigorous accelerated aging tests applied for qualification and they can experience some similar rigorous adverse environmental and mechanical conditions in field applications. Because of this, the connector insert must be capable of withstanding severe conditions, yet maintaining the integrity of the connector construction.
While a few single channel connectors are designed with identical pin termini brought together slidingly within a precision alignment element that can be easily cleaned since both termini can be removed, there are other single channel connectors which are actually small shell-size plug and receptacle connectors like the larger, multi-channel counterparts. These experience the same difficulty in cleaning in field applications as do the multi-channel connector systems.
A special type of multi-channel connectors is the hermaphroditic connector. This connector has identical connector halves which have both protruding pin termini and recessed socket termini. The interface arrangement is usually such that when one of the connector halves is brought into position having a common center line with the other identical connector half and are brought together in an orientation where they are each 180.degree. displaced from the other half, the connector halves meet and are matable. To couple the connector halves together, the coupling ring on one of the connector halves is used to bring forward and mate to the other connector half.
The basic problem with these connectors is to maintain the integrity of the connector while somehow providing for a means to clean the connector socket termini in the recessed alignment bushing cavities. This means that whatever is designed as an improvement to provide means of field cleaning must be as rugged as the connector in which the design is introduced, both mechanically and environmentally.
It is one object of the invention to provide a connector system for field applications that is easy to clean.
Another object of the present invention is to provide a connector system for field application that is mechanically and environmentally rugged.
Another object of the present invention is to provide a connector system that is easy to clean but maintain the integrity of the connector system.
Yet another object of the present invention is to provide a connector system that is easy to clean, rugged in construction and applicable to single-channel, multiple channel, hermaphroditic, plug/receptacle, plug/feedthrough/plug or other connector mechanism.